[Feat]: Add CMake install support for native C++ library

[noclone]

What is your idea?

The README mentions that web-ifc can be used as a standalone C++ library, and the CMakeLists.txt builds a web-ifc-library static library target.
However, there's no install() command, making it difficult to use web-ifc as a dependency in other C++ projects.

[noclone]

I'm willing to submit a PR for this if there's interest.

[mwestphal]

@agviegas, after our discussion on your forum, we (@noclone , myself and others) will look into contributing this. thanks!

[noclone]

#1808 PR created